The mother of the juvenile, the youngest of six members of the gang accused of the attack, recalled the son who left home five or six years ago for the bright lights, and seemed stunned by the accusation against him.

In a village in India's Uttar Pradesh state, a woman sits hunched on the ground in a green shawl, visibly weak and shivering in the January cold. She says she has not eaten for days, and neither have her five young children.

She has never heard of Manmohan Singh, India's prime minister, having never ventured further from her village than a nearby market town, and ekes out a living working in potato fields on other people's land.

Her eldest son left home when he was 11. He never returned, and the woman thought he was dead. The first news she got of him was when police from New Delhi turned up at her brick hut to say he had been arrested for the gang-rape and death of a student, a crime whose brutality stunned India.

In an interview with Reuters, the mother of the juvenile, the youngest of six members of the gang accused of the attack, recalled the son who left home five or six years ago for the bright lights, and seemed stunned by the accusation against him.

"Today, the infamy he earned is eating me up," his mother said as villagers stood and stared. "I can't even sit with two other people in the village because of the shame that my son has brought to the family."

A 23-year-old paramedical student was beaten and raped on a moving bus in the Indian capital on Dec. 16. She was left bleeding on a highway and died two weeks later from internal injuries.

The five men who have been charged with rape and murder are all expected to plead not guilty. One says police tortured him. The sixth member of the gang, the woman's son, is being processed as a juvenile and has not been charged. He will be tried separately.

Police have said they are conducting bone tests to determine his age as they suspect he may be over 18 years old. Reuters is withholding his name for this story. The trial of the five men is due to start within weeks.

It is from a life of rural penury that the youth sought to escape, one of about two million Indians who migrate to cities every year, chasing an economic boom that has propelled India for the past two decades but has trickled down slowly to its poor.

Conversations with relatives, neighbours and police show the extent to which the accused lived on the margins of the city's emerging prosperity, holding menial jobs and living in a slum. Their lives stand in contrast with that of the victim.

She was also from a humble background but funded her studies by taking a job in one of the call centres that are a hallmark of modern India's economy and have helped build an aspirational new middle class.

According to his mother, the youth joined a group of other village boys travelling to New Delhi, found work in a roadside eatery and - for the first year - used to send 600 rupees ($11) a month back to his family.

After he stopped sending money, his mother never heard from him again. At first she thought he might have been forced into bonded labour. Later, she presumed he was dead.

A couple of months before the rape, she consulted a Hindu holy man about her son, whom she remembered as a good boy. "The holy man told me that someone has practiced some black magic on him, but that he would come back," she said.

Living on the breadline and with a husband who is mentally ill, the mother works in fields with her daughters to feed her family. Halfway through the conversation with Reuters, she fainted, apparently from hunger, and had to be carried to bed. About half of her village are landless labourers, and about a quarter of all men migrate to cities in search of work, according to farmer Vijay Pal.

The details of the boy's life after he left his village are patchy. Even his fellow accused did not know his real name and called him by an assumed name, a senior police officer told Reuters.

Police described him as a "freelancer" at a Delhi bus station, cleaning buses and running errands for drivers. "He was a helper on buses who would solicit customers by calling out to them in a sing-song tone," the officer said.

He was popular with the contractors who ran the bus services and frequently changed jobs. It was during this time that he met Ram Singh, the main accused in the case, whom he had gone to meet on the day of the attack in the hope of getting back money that Singh had borrowed from him, police said.

The juvenile went to Singh's house to claim 8,000 rupees ($150) but Singh invited him to stay for food instead, according to a police report. After the attack, police say they found the juvenile's blood-stained clothes on Singh's roof.

In an interview with Reuters, the friend of the victim who had accompanied her on the bus, and who was also beaten, said the juvenile had beckoned the pair to board. "There was a young boy who was standing at the door of the bus and calling passengers in," the friend said by telephone.

"He had a light moustache, very sharp eyes and a very sweet demeanour. He was thin and was calling out to people saying 'come sister, please sit'." When they started assaulting the victim's friend, the juvenile "was one of the first to attack me", he said.

Singh and three of the other accused lived in a poor pocket in the otherwise largely middle-class Delhi neighbourhood of RK Puram, whose wide streets and tree-lined boulevards contrast with the dark lanes, communal taps and open sewers where Singh lived.

Many of the people who live there are migrants, working as electricians, auto-rickshaw drivers, day labourers, bus drivers, mechanics and street vendors. Singh was a bus driver, despite an accident in 2009 that fractured his right arm so badly that doctors had to insert a rod to support it. He appeared on a reality television show in a compensation dispute with a bus owner, who in turn accused Singh of "drunken, negligent and rash driving".

Singh's neighbours describe him as a heavy drinker with a temper. One young woman said he used to get embroiled in violent rows and a relative recalls a physical altercation with her husband. "

India's rapid growth over the past two decades, kickstarted by a period of free-market economic reforms, accelerated the process of urbanisation. The world of the juvenile's mother is still one where carts drawn by horses and bullocks ply the lanes, and dung cakes are stacked in villages to be used as a fuel.

But in the cities, the old barriers of caste and gender are being eroded as India prospers. It is in this world that Vinay Sharma, another of the accused, wanted to make his mark, and aspired to the kind of life that the victim was striving for.

Passionate about boxing and body-building, Sharma earned $55 a month as a helper in a gym and wanted to enrol on a correspondence course, according to his mother and neighbours in the slum where he lived.

"He always used to say 'I will make it big in life'," said his mother, Champa Devi. Like the juvenile and the victim, Sharma's family is originally from Uttar Pradesh, a state of some 200 million people where poverty is entrenched.

"When the police came around 4 or 4.30 in the evening, he was at home", his mother said. "I ran after him when they were taking him away. They would not even tell me why. Even he kept insisting 'Ma, go back home, nothing will happen to me. They are just taking me to ask some questions. I will be back soon.' But that was the last I saw of him."

(Additional reporting by Satarupa Bhattacharjya in NEW DELHI; Sharat Pradhan and Mansi Thapliyal in BADAUN; Editing by John Chalmers and Robert Birsel)